用#FFFF2222的string生成color

private Color ToColor(string colorName)
{
if (colorName.StartsWith("#"))
colorName = colorName.Replace("#", string.Empty);
int v = int.Parse(colorName, System.Globalization.NumberStyles.HexNumber);
return new Color()
{
A = Convert.ToByte((v >> 24) & 255),
R = Convert.ToByte((v >> 16) & 255),
G = Convert.ToByte((v >> 8) & 255),
B = Convert.ToByte((v >> 0) & 255)
};
}

LayoutRoot.Background = new SolidColorBrush(ToColor("#FFFF2222"));